WASHINGTON — The efforts by President Trump to keep America white are getting increasingly dark.

Make no mistake: What's happening on Capitol Hill this week, at Trump's behest, is nothing other than an attempt by Republicans to slow the inexorable march toward that point at midcentury when the United States becomes a majority-minority nation.

In the long run, they are merely putting a finger in the dike. But in the short term, the Trump-backed immigration proposal, combined with other recent moves by the administration and its allies — support for voter suppression, gerrymandering and various other schemes to disenfranchise minority voters — could extend the white hegemony that brought Trump to power and sustains Republicans.

For ages, Republicans said that their beef was with illegal immigrants and that legal immigrants should be embraced and welcomed. No longer. In the immigration fight on the Hill, there is broad bipartisan consensus to legalize the "dreamers" — undocumented immigrants brought here as children — and to fortify border security. The dispute is really about the Trump proposal to rein in legal immigration by undoing the family-based approach, in which immigrants petition to bring over immediate family, that has always been at the heart of U.S. immigration.

Though details aren't yet known, estimates are that the legislation would cut legal immigration, currently 1.1 million per year, by 300,000 to 500,000 annually.

Essentially, Trump and the Republicans are threatening to make nearly 700,000 dreamers subject to deportation unless Democrats agree to close the door to tens of millions of future legal immigrants.

This won't stop the loss of a white majority; the youthful Hispanic population already here, with its higher fertility rate, makes that inevitable. "It's almost impossible to become whiter as a country," the Brookings Institution demographer William H. Frey tells me. "It's like a demographic tsunami. There aren't enough people in Norway to migrate here."

But the GOP might delay by a few years the point at which the United States becomes majority-minority, now expected in 2044. Minorities vote at lower rates than whites (52.7 percent in 2016 vs. 65.3 percent for whites), so, if Republicans can sustain that disparity, the white voting majority that the party relies on could last several years beyond 2044.

Republicans may be acting out of self-interest rather than any racial animus. But if one were to devise a diabolical plan to suppress nonwhite votes, it would look much like what they are doing.

The administration asked to include a question about citizenship in the 2020 Census, which will determine the apportionment of House seats. This would suppress census participation among the 7 percent of residents who are not citizens — even those here legally — thus causing Latinos to be undercounted.

The administration argued last month before the Supreme Court in favor of an Ohio practice of purging voters from registration rolls if they fail to vote over two federal election cycles. Because of minority voters' lower participation rates, they would be purged from the rolls in higher numbers.

The administration has given tacit support to other voter-suppression efforts in the states, in the form of voter ID laws and restrictions on early voting. Trump nominated, and the Senate Judiciary Committee has approved, a district court nominee, Thomas Farr, who helped draft and defend the most egregious voter-suppression and gerrymandering laws in the country. Farr unsuccessfully argued for North Carolina's voter ID law, which was struck down by an appellate court because it targeted African-Americans "with almost surgical precision."

The Republican National Committee, which is under Trump's authority, also weighed in on a current Supreme Court case in favor of political gerrymandering, often used to dilute minority votes.

Trump himself has continued to stir up fears, often based on falsehoods, of a crime wave caused by illegal immigrants, and he has requested billions of dollars to step up deportations. (At the same time, he has proposed a 5 percent cut to federal education funding, much of it for programs benefiting the urban poor, disproportionately minorities.)

This is, of course, what you would expect from an administration whose chief law enforcement official, Attorney General Jeff Sessions, just hailed "the Anglo-American heritage of law enforcement." This phrase — an ad lib while reading from a prepared text — would be easier to excuse as an innocent reference to common law if Sessions didn't carry so much racial baggage, and if his boss hadn't just referred to "s***hole" African countries.

Republicans can't keep America white, but they can stop sullying themselves in the attempt.